so changed clutch+brake levers both are exactly the same size as old ones. ( at least i thought they were ) problem is the front brake lever just misses the micro switch to operate the brake light . already disposed of old ones. any ideas welcome

I'd sand the paint off the area on your new levers, then glop a blob of J-B Weld epoxy in place. Wait for it to cure, then file it down to the proper shape and position needed to actuate the switch. Lastly, a quick shot of spray paint to make it all look nice.